4,1

I have derived the terms in a rather laborius way (see the Maple program), following the Haight paper, where the signed sequence occurs. The simple g.f. for the positive sequence is conjectured by analogy with A006043. For the signed sequence it is, obviously, 6x^4/(1+4x)^4. The Maple program, probably not the simplest one, is for the signed sequence. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 29 2004

F. A. Haight, Overflow at a traffic light, Biometrika, 46 (1959), 420-424.

It seems that G.f.= 6x^4/(1-4x)^4 (for the positive sequence). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 29 2004

A:=(u, r)->r*u^(u-r-1)/(u-r)!: a:=proc(i, j) if j>i+1 then 0 elif j=i+1 then 1 else A(z-j+1, z-i) fi end: with(linalg): B:=proc(z, x) if z=x then 1 else (-1)^(z+x)*det(matrix(z-x, z-x, a)) fi end: seq(expand(subs(z=k, (z-1)!*B(k, 4))), k=4..26);

Adjacent sequences: A006041 A006042 A006043 this_sequence A006045 A006046 A006047

Sequence in context: A053338 A055358 A030989 this_sequence A001805 A038094 A126151

sign

njas

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 29 2004